History of Pangaea

 
This novel describes an alternate history where humans evolved while Pangaea
was still intact. Without the barriers to exchange of domesticable animals,
among other factors, the natives of Africa gained a technological and
organizational advantage over the humans of Europe rather than the other way
around, and made Europeans their slaves. At the time of the story, slavery has
been abolished, but segregation operates to keep the Crosses (the Africans) in
control of the noughts (Europeans). Also, the close proximity of the various nations
of the world in a single supercontinent and the lack of natural defenses have forced
 the nations of the world to learn to  cooperate. An organization called the
Pangaean Economic Community exists, and seems to be similar to the United Nations in
 scope but similar to the European Union in powers, and it is playing a role in forcing
change.